Absorbing prokaryotic cells. This theory is called the endosymbiotic theory.
The early prokaryotic cells that were absorbed likely evolved into mitochondria and chloroplasts, membrane-bound organelles with their own DNA in single chromosomes and their own ribosomes.
Answer: Photosynthesis
Explanation: Photosynthesis removes CO2 from the atmosphere and replaces it with O2. Respiration takes O2 from the atmosphere and replaces it with CO2.
Plant cells have cell walls, while animal cells don't have cell walls.
According to the CDC, tooth decay
affects more than one-fourth of U.S. children aged 2 to 5.Tooth decay is the
damage of the structure of the tooth which is caused by acids that are produced
when sugar is being broken down by plaque bacteria in the mouth. Tooth decay is the primary cause of tooth loss in children in the United
States.
